1. Field of the Invention
The present invention relates to a carrier unit which is a part of a substrate transfer apparatus provided in a substrate processing equipment and adapted to carry in and carry out substrates. Particularly, the present invention relates to a carrier unit of an equipment front end module (EFEM) which is a substrate transfer apparatus provided in a semiconductor processing equipment.
2. Description of the Related Art
FIG. 31 is a section showing a part of semiconductor processing equipment 1 of the related art. The semiconductor processing equipment 1 is configured to include a wafer processing apparatus 2 and a wafer transfer apparatus 3. The internal space of the semiconductor processing equipment 1 is filled with an atmospheric gas which is kept at a predetermined cleanliness level. Thus, attachment of foreign matters floating in the atmosphere to wafers 4 to be processed in this system can be prevented. The semiconductor wafer 4 are carried into the semiconductor processing equipment 1 while being contained in a front opening unified pod (also merely referred to as a “FOUP”) 5 which is a substrate container.
The wafer transfer apparatus 3 takes unprocessed wafers 4 out of the FOUP 5, transfers the taken-out wafers 4 through a ready space 9, and then supplies them to the wafer processing apparatus 2. In addition, the wafer transfer apparatus 3 takes processed wafers 4 out of the wafer processing apparatus 2, transfers the taken-out wafers 4 through the ready space 9, and then brings them contained again in the FOUP 5. Specifically, the wafer transfer apparatus 3 includes a FOUP opener 6 (hereinafter, referred to as an opener 6), a robot 7, and ready space forming walls forming the ready space 9. The internal space 12 of the FOUP and ready space 9 are made airtight against the external space 13 and maintained such that very few dust particles exist therein, respectively.
In the main frame 8 which constitutes a part of the ready space forming walls, a wafer-side opening is formed through which each wafer 4 can be passed. The opener 6 is secured to the main frame 8, and a FOUP supporting portion 11 is provided for supporting the FOUP 5 in the external space 13. The opener 6 has an opener-side door adapted to close the wafer-side opening to tightly shut the ready space 9 against the external space.
The opener 6 serves to make the space 12 in the FOUP be in communication with the ready space 9 by opening a FOUP-side door of the FOUP 5 and the opener-side door of the opener 6 while preventing the outside air from flowing into the spaces. In this state, the robot 7 carries each wafer 4 from the FOUP 5 into the wafer processing apparatus 2, as well as carries it from the wafer processing apparatus 2 into the FOUP 5. On the other hand, when the opener 6 closes both of the FOUP-side door and the opener-side door, the internal space 12 of the FOUP 5 and the ready space 9 are shut tightly against the outside air, thus separating the FOUP 5 from the semiconductor processing apparatus 1.
In the related art disclosed in Japanese Patent Laid-Open Publication No. 2005-525688, the main frame 8 includes a front face 8a to which parts constituting the opener 6 are secured. Also, the main frame 8 has a rear face 8b to which parts constituting the robot 7 are secured.
The robot 7 of the wafer transfer apparatus 3 according for supporting a robot hand greater, in order to prevent the reaction force associated with the force to be generated due to operation of the robot hand upon transferring each wafer from being transmitted to the main frame 8 of the wafer transfer apparatus 3. Namely, due to such configuration, the transmission of the reaction force associated with the force to be generated from the robot hand to the main frame 8 can be prevented.
In the related art described above, the base 10 of the robot 7 is designed to have higher rigidity in any given direction along which the base would be fixed in order to have the robot 7 transfer each substrate, irrespectively of the state of being fixed to the main frame 8. Consequently, the number of parts enlarged. In addition, because of the need to have greater rigidity in many directions, the production cost of the robot 7 must be increased.
Furthermore, even though making the rigidity of the base frame 8 is insufficient, the amount of deformation of the main frame 8 caused by force to be exerted from the robot 7 may tend to exceed a predetermined allowable amount of deformation, leading to undesired displacement of the robot hand, thus causing malfunctioning in the wafer conveyance. Contrary, when the rigidity of the main frame 8 is unduely high, value needed. As a result, the quality concerning the vibration control of the wafer transfer apparatus 3 tends to be excessively high, which obstructs simplification of the structure, weight reduction as well as cost reduction. Such a problem can be commonly seen in other apparatuses than the wafer transfer apparatus, for example, glass substrate transfer apparatuses for carrying glass substrates.